Finish Cutting of Hardened Steel (1st Report)

Influence of Workpiece Hardness for the Forming of Built-up Edge

Abstract

The forming of built-up edge is studied in the cutting of hardened steel. The built-up edge forms in cutting of low hardened steel, however it has been found that the built-up edge does not form in any cutting speeds in the cutting of hardened steel whose hardness exceeds a certain value (defined as critical hardness). Then, this disappearing mechanism is discussed. As a result, conclusions are obtained that this mechanism is owing to the relation between the maximum hardness to which the built-up edge can reach and the workpiece hardness, and the critical hardness is about a half of the maximum hardness of the built-up edge. Besides, the mirror finish is clarified to be possible in the cutting of hardened steel whose hardness exceeds the critical hardness.